equality constraints exposed by patterns mess up constraint inference
When patterns bring (equality) constraints into scope, the inference mechanism for other (unrelated) constraints breaks down.
This is a new problem that appeared between
- ghc-7.7.20121025 and
- ghc-7.7.20121114
I can try to track down the commit if that helps.
Testcase against HEAD attached.
Trac metadata
Trac field | Value |
---|---|
Version | 7.7 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |